view.traitCollection.horizontalSizeClass returning undefined (0) in viewDidLoad

Question

I\'m using a UITextView inside a UIPageViewController, and I want to determine the font size based on the size class of the device.

The first slide of the page view is l

Answer 1

I found that if I use the main screen's traitCollection, instead of the current view, I get the correct size class:

if (UIScreen.main.traitCollection.horizontalSizeClass == .compact) {
    fontSize = "20"
} else {
    fontSize = "28"
}